op = overpowered (violating the balance of the game)
BO = build order (the order in which you build up your early economy)
KaiserWinterfeldt, Norse units really are not weak. Ulfsarks are better than spearmen, and even 1 RC defeats 1 spearman (or 1 ulf) 1 vs 1.
RC are especially strong with regard to the fact that they cost only 2 population space, not to mention their awesome speed. RC will defeat hippikons, because hippikons cost 3 population space (and more resources), so the hippikon owner will have less hippikons, and numbers will more than compensate for the RC's weaker stats.
If you want slower units with more power per unit, then use hill fort units. Generally, you must not forget many Norse units have high speed, so they can outrun the enemy - and show up where he does not expect them to.
If you believe that Norse are weak, there is a very simple way for you to find out: Play a different race - rated. I can assure you that you will encounter lots of Norse online. Then try to make use of their assumed weakness. Try to take advantage of the drawbacks that you described - and see if you can easily beat them. If not, you will soon know why Norse are not really that weak...
Darkness is a state of mind
Valor is the contempt of Death and Pain. (Tacitus)
Problems worthy of attack prove their worth by hitting back. (Piet Hein)